#36522: Assigning expressions to model fields does not work if the field
participates in a composite primary key
-------------------------------------+-------------------------------------
Reporter: Jacob Walls | Type: Bug
Status: new | Component: Database
| layer (models, ORM)
Version: 5.2 | Severity: Release
| blocker
Keywords: | Triage Stage:
compositeprimarykey, F | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
For this model in the test suite:
{{{#!py
class Comment(models.Model):
pk = models.CompositePrimaryKey("tenant", "id")
tenant = models.ForeignKey(
Tenant,
on_delete=models.CASCADE,
related_name="comments",
)
id = models.SmallIntegerField(unique=True, db_column="comment_id")
...
}}}
This fails:
{{{#!diff
diff --git a/tests/composite_pk/test_update.py
b/tests/composite_pk/test_update.py
index 697383b007..e76210e75e 100644
--- a/tests/composite_pk/test_update.py
+++ b/tests/composite_pk/test_update.py
@@ -191,3 +191,7 @@ class CompositePKUpdateTests(TestCase):
)
with self.assertRaisesMessage(FieldError, msg):
Comment.objects.update(text=F("pk"))
+
+ def test_update_fields_expression(self):
+ self.comment_1.id = F("id") + 100
+ self.comment_1.save()
}}}
{{{#!py
======================================================================
ERROR: test_update_fields_expression
(composite_pk.test_update.CompositePKUpdateTests.test_update_fields_expression)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/Users/jwalls/django/django/db/models/fields/__init__.py", line
2130, in get_prep_value
return int(value)
TypeError: int() argument must be a string, a bytes-like object or a real
number, not 'CombinedExpression'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/Users/jwalls/django/tests/composite_pk/test_update.py", line 197,
in test_update_fields_expression
self.comment_1.save()
~~~~~~~~~~~~~~~~~~~^^
File "/Users/jwalls/django/django/db/models/base.py", line 874, in save
self.save_base(
~~~~~~~~~~~~~~^
using=using,
^^^^^^^^^^^^
...<2 lines>...
update_fields=update_fields,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/Users/jwalls/django/django/db/models/base.py", line 966, in
save_base
updated = self._save_table(
raw,
...<4 lines>...
update_fields,
)
File "/Users/jwalls/django/django/db/models/base.py", line 1097, in
_save_table
updated = self._do_update(
base_qs, using, pk_val, values, update_fields, forced_update
)
File "/Users/jwalls/django/django/db/models/base.py", line 1165, in
_do_update
return filtered._update(values) > 0
~~~~~~~~~~~~~~~~^^^^^^^^
File "/Users/jwalls/django/django/db/models/query.py", line 1319, in
_update
return query.get_compiler(self.db).execute_sql(ROW_COUNT)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 2103,
in execute_sql
row_count = super().execute_sql(result_type)
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 1611,
in execute_sql
sql, params = self.as_sql()
~~~~~~~~~~~^^
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 2089,
in as_sql
where, params = self.compile(self.query.where)
~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 578,
in compile
sql, params = node.as_sql(self, self.connection)
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/sql/where.py", line 151, in
as_sql
sql, params = compiler.compile(child)
~~~~~~~~~~~~~~~~^^^^^^^
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 578,
in compile
sql, params = node.as_sql(self, self.connection)
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/fields/tuple_lookups.py",
line 130, in as_sql
return super().as_sql(compiler, connection)
~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/lookups.py", line 407, in
as_sql
return super().as_sql(compiler, connection)
~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/lookups.py", line 239, in
as_sql
rhs_sql, rhs_params = self.process_rhs(compiler, connection)
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/fields/tuple_lookups.py",
line 109, in process_rhs
return compiler.compile(Tuple(*args))
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 576,
in compile
sql, params = vendor_impl(self, self.connection)
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/fields/tuple_lookups.py",
line 46, in as_sqlite
return self.as_sql(compiler, connection)
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/expressions.py", line 1107,
in as_sql
arg_sql, arg_params = compiler.compile(arg)
~~~~~~~~~~~~~~~~^^^^^
File "/Users/jwalls/django/django/db/models/sql/compiler.py", line 576,
in compile
sql, params = vendor_impl(self, self.connection)
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/expressions.py", line 29, in
as_sqlite
sql, params = self.as_sql(compiler, connection, **extra_context)
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jwalls/django/django/db/models/expressions.py", line 1175,
in as_sql
val = output_field.get_db_prep_value(val, connection=connection)
File "/Users/jwalls/django/django/db/models/fields/__init__.py", line
2137, in get_db_prep_value
value = super().get_db_prep_value(value, connection, prepared)
File "/Users/jwalls/django/django/db/models/fields/__init__.py", line
1006, in get_db_prep_value
value = self.get_prep_value(value)
File "/Users/jwalls/django/django/db/models/fields/__init__.py", line
2132, in get_prep_value
raise e.__class__(
"Field '%s' expected a number but got %r." % (self.name, value),
) from e
TypeError: Field 'id' expected a number but got <CombinedExpression:
Col(composite_pk_comment, composite_pk.Comment.id) + Value(100)>.
}}}
----
The `+ 100` is not necessary to reproduce, just there for realism. Error
without is the same: "expected a number but got Col(..."
If support is difficult, a `FieldError` is perhaps better, see
`test_update_value_not_composite()`.
--
Ticket URL: <https://code.djangoproject.com/ticket/36522>
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